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45 terms

3-20: OB/GYN - fetal monitoring

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what are the methods for pre-natal diagnosis
AFP, triple marker screen, quadruple marker screen, chorionic villus sampling, ultrascreen, US, amniocentesis
what is maternal serum alpha fetoprotein (MS-AFP)
produced in fetal liver cells, found in ammniotic fluid and meternal blood
when is AFP found
16-20 weeks
what does elevated AFP mean
neural tube defects (NTD)
what does decreased AFP mean
trisomy 21/18
what is a triple marker screen
Three blood tests (MS-AFP, estriol, B hCG
when is triple marker screen done
15-20 weeks
why do triple marker screen
improves detection over AFP alone: same consequences as AFP
what is a quadruple screen
inhibin-A + MS-AFP, estriol, B hCG (triple screen); hormone in blood made by placenta
when is a quadruple screen done
15-20 weeks
why do a quadruple screen
predicts adverse pregnancy outcome, small baby, still birth
when is chorionic villus sampling done
10-12 weeks
how is chorionic villus sampling done
Catheter passed through cervix into uterus to developing placenta utilizing ultrasound
what is an ultrascreen
Measures blood protein levels and ultrasound for nuchal translucency (thickness of skin on back of fetal neck
when is an ultrascreen done
11-14 weeks
what does ultrascreen test for
downs, trisomy 18
when can you visualize IUP with US
5 weeks
what is US used for
detects anomalies, twins, placenta location, abnormal pregnancy, gestational age
what is gestational age dependent on
Abdominal circumference, Head circumference, Biparietal diameter of head, Femur length, Crown to rump length (first trimester)
when is amniocentesis done
15-18 weeks
how is amniocentesis done
needle passed thorugh mothers lower abdomen into amniotic cavity
what are the two types of fetal monitoring
internal and external
internal fetal monitoring
fetal scalp electrode, xervix must be dilated and membranes ruptured, high quality recordings.
external fetal monitoring
transducer on mother's abdomen. Does not require cervical dilation or membrane rupture. FHR quality varies with position and maternal obesity
what is normal HR of fetus
110-160
what is marked change in fetal heart rate
greater than 25
what are periodic changes
accelerations and decelerations in FHR associated with contractions
what are accelerations
Seen with fetal movement or stimulation. Abrupt
increase in fetal heart rate above baseline
what are early deceleration
Decrease in response to contractions.; Onset with onset of contractions, duration is
length of contraction
why do early deceleration happen
Due to fetal head compression during contraction resulting in fetal vagal stimulation
what is variable deceleration
Decrease in FHR not associated with contractions
why do variable deceleration happen
umbilical cord compression
what is late deceleration
Gradual onset of decreased FHR and gradual return to normal
why does late deceleration happen
uteroplacental insufficency
what is not assuring fetal scalp pH
less than 7.2
what is a non stress test
Transducer placed on mother's abdomen to record FHR and reactivity
what is non reactive NST
Accelerations not present. Fetus can be compromised, asleep, immature, or sedated
what do you do with non reactive NST
wake fetus with vibro-acuoustic stimulation
what is a contraction stress test (CST)
Uterine contractions decrease blood flow to the placenta. Need spontaneous contractions or contractions induced by oxytocin.
what is a negative CST
No late decelerations in presence of contractions
what is a positive CST
repetitive late decelerations
what is a biophysical profile
5 parameters, two points each: NST reactivity, extremity tone, chest wall movements, gross body movements, amniotic fluid volume
what are the results of a biophysical profile
8-10 = good: 4-6 = deliver if greater than 36 weeks
what is fetal scalp sampling
Used in labor if question of fetal well being;
how is fetal scalp sampling done
cone placed in vagina to visualize fetal head; prick scalp and draw blood